Find x Using the Constant of Variation

When two variable quantities have a constant ratio, their relationship is called a direct variation. It is said that one variable varies directly as the other. The formula for direct variation is ${\displaystyle y=kx}$, where ${\displaystyle k}$ is the constant of variation.

Solve the equation for ${\displaystyle k}$, the constant of variation.

Replace the variables ${\displaystyle x}$ and ${\displaystyle y}$ with the actual values.

Multiply the numerator by the reciprocal of the denominator.

Use the formula ${\displaystyle x=ky}$ to substitute ${\displaystyle \frac{1}{15y}}$ for ${\displaystyle k}$ and ${\displaystyle 2}$ for ${\displaystyle y}$.